In the handling of high pressure fluids it is known to provide hose connectors that include an internal shut-off or check valve. The check valve closes automatically on decoupling of the connector in order to prevent the leakage of gas or liquid from the disconnected coupling. Auto-shut off connectors are useful as well on high pressure air lines to prevent such lines from thrashing when disconnected.
Examples of patents that have issued for this class of connector include U.S. Pat. No. 4,865,077 to Batchen, and U.S. Pat. No. 4,827,977 to Fink and Husky. Various commercial models previously in use include the HANSEN Coupling made by the Hansen Coupling Division of Tuthill Corporation of Cleveland, Ohio, TOMCO connectors by Tomco Division of C.S.P. Inc. of Willowick, Ohio, and HOFMANN connectors by Holmann Engineering Co. Inc. of Burr Ridge, Ill.
In the Hansen design, which is typical, a male portion of the connector, called hereafter the "plug", is held in place within a female portion of the connector, called the "female coupling", by radially located steel balls. These balls are contained in a race around the inner circumference of the female coupling. The steel balls partially inter-fit into a complementary groove formed on the outer circumference of the plug, once the connector portions are assembled. The steel balls are radially displaceable within their race, but are held in an advanced, groove-engaging, locking position by an outer locking/release ring.
This outer ring is displaceable longitudinally, and carries an inner groove into which the steel balls may be displaced, once this groove is aligned with such balls. Adjacent the groove, an inner locking surface on the ring holds the balls in their advanced, locking position within the race when advanced to overlie the balls.
The locking/release ring is biased by a spring to advance along the connector until the locking surface overlies the steel balls. By overcoming this bias, i.e. by displacing the locking/release ring, the groove may be aligned with the steel balls to effect engagement and disengagement of the coupler portions.
The Hansen coupling requires manipulation to effect engagement of the coupling. That is, the locking/release ring must be displaced manually to allow the steel balls to recede within their race while coupling is effected. Other connectors provide for automatic engagement upon insertion of the plug into the female coupling.
In the field, connectors of the Hansen type have been rendered into auto-disengaging couplings that disconnect under tension developed by pulling on the line leading to the connector. This has been effected by anchoring the release ring to a stationary object by a linkage, such as a chain. Tension on the line causes the connector to move with respect to the release ring. Upon sufficient displacement of the connector with respect to the release ring, release is effected.
In the Hansen connector, the steel balls, which serve as a latch means, are continually subject to a pressure, arising from the tendency of the connector portions to separate. This pressure, if it were not for the presence of the locking/release ring in its appropriate position, would displace the steel balls and effect release of the coupling.
The Mansen-type coupling is relatively insensitive to line pressure as the thrust on the steel balls is partially absorbed by the race, and the frictional resistance between the locking/release ring and the steel balls is correspondingly reduced. Nevertheless, some resistance exists, and this residual resistance is proportional to line pressure.
Another type of connector in this field is that manufactured by S.A. Des Etablissements Staubli of France. This device, depicted in European Patent Application 82420113.1 and published as EP-0-077-743-A1, shows a connector wherein a transverse activating pin provides a double latching action for release of the connector. The focus of this patent is on the double latching action.
In both the Hansen and Staubli type connectors a single internal check valve, biased to close by a spring, may be provided. This check valve can be contained within a female portion of the connector, but could alternately or also be located in the male or plug portion. In all cases a probe carried on the opposing portion of the connector, when assembled, holds the check valve open.
The Staubli connector differs from the Hansen connector in that engagement of the connector does not require any manipulation of a locking ring or the like. Instead, engagement is effected by the mere application of insertion pressure on the plug into the female coupling whereby a bayonet-like engagement is effected. The barb-equivalent on the plug portion of the Staubli connector is a ring with a bevelled forward edge and a perpendicular rearward side. This rearward side engages with and is held in place by a first latching portion of the transverse activating pin, once the connector is assembled.
The double latching effect arising on uncoupling in the Staubli connector is achieved by a second latch portion on the activating pin that stops the withdrawal of the male plug portion of the connector after partial disconnection occurs. This interruption of the disengagement process allows the check valve to close and the line carrying the plug, which lacks its own check valve, to depressurize without thrashing. Release of the second latch allows full withdrawal to be effected.
The Staubli connector is manually operated. However, its feature of reliance on a transverse activating pin to effect decoupling can be adapted to provide a tension-activated auto-disengaging connector. Such a tension-activated connector is useful particularly where compressed gas is being pumped into a vehicle holding tank, as where cars are fueled by compressed natural gas. On occasion an operator may decide to move the vehicle, forgetting to manually disconnect the coupling on the fluid feed line. By providing a tension-activated coupler the risks of having a ruptured fluid line are eliminated.
The activating pin in the Staubli connector differs from the locking/release ring in the Hansen type connector in that the Staubli connector requires that pressure be applied to the activating pin or actuator so that unlatching of the connector may be effected. Because the barbed ring on the plug is held by a latch that is displaced transversely, there is no tendency for line pressure to disengage the latch. A positive displacement of the actuator by application of actuating pressure is necessary in order to cause the latch to disengage.
In a separate application by Gordon Bryce, a tension-activated auto-disengaging coupler that contains an actuator for the latch is disclosed. The actuator therein; is biased by a spring to resist actuation but contains a means that will automatically effect disengagement when a pro-determined tension is applied to the coupling. This coupler is based on a transversely moving latch similar in some respects to the Staubli connector.
In the Staubli connector, the frictional resistance to displacement of the first latch proportional to line pressure. Such friction arises at the point of contact between the first latch and the rear side of the barbed ring on the male plug. This friction increases the effort required to displace the transverse activating pin. Such resistance is particularly sensitive to line pressure because the first latch in the Staubli connector is displaced transversely to the direction in which the connector portions connect and disconnect.
Accordingly, it is an object of this invention is to reduce the effort required to unlatch an auto-disconnecting connector under conditions of high line pressure.
The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention will then be further described, and defined, in each of the individual claims which conclude this Specification.